It's suggested, but never confirmed, in Remember When, that Larry Boy gave the Feds the location of Willie Overall's body. Later in the episode, however, Silvio says Larry told the Feds Jackie Aprile killed Willie Overall, not Tony. Silvio adds, happily, "[Larry] covered your ass", which implies Larry knows it was actually Tony who did it.

Did Larry flip, or was he just fucking around with the Feds to amuse himself, "trolling" them in essence?

Nah,he wasn't trolling them. He was giving them misinformation purposefully that could maybe help him out and not hurt any of his friends. Pretty smart.

His information led to them digging up the body in the first place, which prompted Tony, the boss, to have to leave town for several days. Tony would have to be suspicious at this point. My guess is Larry flipped, we just don't see it.

They don't really indicate. Just as likely as him flipping and dangling a body for leniency is that they threw the body on him to add more years for the probation violation and he had to somehow deflect a murder charge away from his sentence.

Silvio tells Tony at the end of the episode that Larry put the body on Jackie Aprile. Larry didn't rat on anyone. He just gave the FBI enough info to get out from under.

He either had a proffer session or he flipped. Could have been either. Remember, in the show Larry was indicted with Junior in 1999. As of 2007, we see him get popped for violating house arrest. That's 8 years, a long time.

Its feasible that after all that time he gave cooperation serious consideration, and finally decided to do it. Remember, in one episode in season 5, he laments to Bobby about Tony's unwillingness to "leave his own family out of the fucking frying pan" while allowing others to rot.

If I had to guess, after 8 years of seeing Tony having immense financial success while he sat awaiting trial, he said f it and signed on with the feds.

Sure, he may not have given up Tony on the Willie Overall thing, but that doesn't mean he would not have or hadn't already given up Tony on other crimes.

I reckon Larry was shelved afterwards though there's no way they'd let him back after that

I can see Larry pulling a Bulger. Capo of the biggest crew in the family, who has watched Tony's behavior of putting his own blood family first instead of his crime family. He had a lot of motive to give the feds information, while staying in the streets. Think of this, he put the Willie hit on Jackie cause then that leaves Tony on the streets, if Tony went to jail or prison, New York would not be able to get to him maybe, or even Larry sending a couple of his soldiers to kill Tony. Killing Tony, he would have to kill Paulie as well. Larry had plenty of opportunities to kill Tony, but he does not seem like the character to get his hands dirty.

Some of you guys are so out there with the Soprano's fan theory. Is this shit you honestly believe or are you just on here to stir the pot?

Yeah, really. I mean, what are people doing discussing a tv show on a forum designated for the tv show? Weirdos...